Voith Turbo Inc. recently supplied Gillig LLC with 70 DIWA.5 automatic transmissions for buses being delivered to Portland, Oregon's TriMet. The transmissions are equipped with two advanced fuel-saving features: Voith’s patented gear-shifting program SensoTop and the ANS-function (Automatic Neutral Shift).
 
The SensoTop program enables the transmission’s control system to automatically adapt gear-shifting points based on acceleration, vehicle load, and topography of the route to achieve optimal fuel economy. A recent year-long field test, conducted in six cities with varying topographies, has shown that SensoTop provided the transit systems with up to 7% in additional fuel savings, according to Voith officials.
 
Voith’s ANS feature interrupts the power flow between the engine and transmission automatically when the vehicle is at a stop, thereby reducing the fuel necessary to idle the engine.

“Transit buses can spend more than 50% of their operating time at idle while loading and unloading passengers or while stopped at traffic lights,” said Tracey Johnson, Key Account OEM Manager at Voith Turbo U.S. “By activating ANS during these stops, significant reductions in fuel consumption can be realized.”
 
The new buses are replacing a portion of TriMet’s older buses, and began entering service in late July. Delivery is expected to continue throughout the fall, with three to five buses being delivered each week. SensoTop and ANS technology are available on new buses like those manufactured by Gillig LLC as well as for retrofits on existing buses equipped with Voith DIWA.5 automatic transmissions.